The choice between "that ... is" and "that ... be" depends on the context and the verb tense you want to use. Here's a breakdown of each construction:
"That ... is": This construction is used when you want to state or describe something as a fact or reality. It is commonly used in present or past tenses.
Example:
"I believe that the Earth is round." (present tense)
"He claimed that the movie was entertaining." (past tense)
In these examples, "is" and "was" are used to indicate the factual nature or state of the subject being described.
"That ... be": This construction is used when you want to express a hypothetical, uncertain, or subjective situation. It is commonly used in subjunctive or conditional contexts.
Example:
"It is important that he be on time for the meeting." (subjunctive)
"If it rains, I suggest that we be prepared." (conditional)
In these examples, "be" is used to express a hypothetical or desired state of affairs, rather than stating a fact.
It's important to note that the use of the subjunctive mood, including the "that ... be" construction, can vary depending on the dialect or formality of English. In some contexts, the indicative mood (using "is" or "was") is used instead of the subjunctive.
In summary, "that ... is" is used to state a fact or describe something in a present or past tense, while "that ... be" is used to express a hypothetical or subjective situation, often in the subjunctive or conditional mood.
